Start disabling GYP by default in runhooks in some configurations.

build/gyp_chromium.py

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """This script is wrapper for Chromium that adds some support for how GYP
 is invoked by Chromium beyond what can be done in the gclient hooks.
 """
 
 import argparse
 import gc
@@ skipping 302 matching lines @@
 
   args.extend(
       ['-I' + i for i in additional_include_files(supplemental_includes, args)])
 
   args.extend(['-D', 'gyp_output_dir=' + GetOutputDirectory()])
 
   mac_toolchain_dir = mac_toolchain.GetToolchainDirectory()
   if mac_toolchain_dir:
     args.append('-Gmac_toolchain_dir=' + mac_toolchain_dir)
 
+  # TODO(crbug.com/432967) - We are eventually going to switch GYP off
+  # by default for all Chromium builds, so this list of configurations
+  # will get broader and broader.
+  running_as_hook = '--running-as-hook'
+  if (running_as_hook in args and
+      os.environ.get('GYP_CHROMIUM_NO_ACTION', None) != '0' and
+      (sys.platform.startswith('linux') and not gyp_vars_dict)):
+    print 'GYP is now disabled in this configuration by default in runhooks.\n'
+    print 'If you really want to run this, either run '
+    print '`python build/gyp_chromium.py` explicitly by hand'
+    print 'or set the environment variable GYP_CHROMIUM_NO_ACTION=0.'
+    sys.exit(0)
+
+  if running_as_hook in args:
+    args.remove(running_as_hook)
+
   if not use_analyzer:
     print 'Updating projects from gyp files...'
     sys.stdout.flush()
 
   # Off we go...
   gyp_rc = gyp.main(args)
 
   if not use_analyzer:
     vs2013_runtime_dll_dirs = vs_toolchain.SetEnvironmentAndGetRuntimeDllDirs()
     if vs2013_runtime_dll_dirs:
       x64_runtime, x86_runtime = vs2013_runtime_dll_dirs
       vs_toolchain.CopyVsRuntimeDlls(
         os.path.join(chrome_src, GetOutputDirectory()),
         (x86_runtime, x64_runtime))
 
   sys.exit(gyp_rc)
 
 if __name__ == '__main__':
   sys.exit(main())